When the conversation turns to Hercule Poirot, though, it's likely to stop with one name: David Suchet, who has devoted much of his career to playing Agatha Christie's pathologically fussy Belgian detective and has, at last, filmed every one of the author's Poirot novels and short stories and the lone play for television. The first two of the final five episodes will air this Sunday and next on PBS, while the last three will premiere on Acorn TV in August and then be made available to public broadcasting stations in November.

The character is so brilliantly conceived that he's been well treated by other actors - Peter Ustinov and Albert Finney, among them. But Suchet has secured a lock on Poirot no one is likely to break, not only because he's played him more often than anyone else but also because of the intelligence of his performances - the way he purses his lips, the funny little walk, the keenly observant stare that so contradicts the almost silly mannerisms, and that signature sculpted mustache.

The first of the two PBS episodes, "The Big Four," begins with a sardonic joke: Hercule Poirot is dead. Of course, we don't really believe it, but still, here we are at graveside with his old friends and colleagues - his housekeeper Miss Lemon (Pauline Moran), Capt. Hastings (Hugh Fraser), Chief Inspector Japp (Philip Jackson) and its more recent member, George the valet (David Yelland).

While we're still waiting for the gotcha, one of the mourners tosses Poirot's walking stick onto the coffin, and we do think for a second that Poirot may really be dead.

A flashback takes us to the beginning of the story, superbly adapted by Mark Gatiss, as Poirot attends a highly anticipated chess match between a retired and reclusive Russian grand master (Michael Culkin) and a leader of the Peace Party named Abe Ryland (James Carroll Jordan). On the second move, the Russian collapses and dies, seemingly of natural causes, but of course, it's murder.

With the aid of his old gang, and in spite of the interference of a scoop-obsessed reporter named Tysoe (Tom Brooke), Poirot carefully unravels the complicated mystery as other characters meet grisly ends. The solution seems to turn on finding the identity of the Big Four, which Poirot does in a delightfully brilliant way.

"Dead Man's Folly" brings the return of Poirot's friend and occasional annoyance, Ariadne Oliver (Zoe Wanamaker), who has been hired by a nouveau riche lug named Sir George Stubbs (Sean Pertwee) to stage a murder mystery game for a country party. Ariadne is convinced that a real murder will occur, although she has no evidence beyond her instinct to suggest that possibility.

Soon enough, though, George's seemingly dim-witted younger wife Hattie (Stephanie Leonidas) disappears, a young village girl is found murdered, and a grizzled ferryman dies accidentally. The eventual solution tests our suspension of disbelief without entirely snapping it in two because, after all, it's Agatha Christie and because just listening to Suchet deliver Poirot's extended solution "aria" is an experience most delicious, as Poirot might say. Nick Dear has done wonders with his adaptation of the original material.

"Poirot" has often drawn major actors for guest roles and so it is with "Folly": Sinéad Cusack's performance as Mrs. Folliat almost steals the whole show. Truth be told, several of the other characters are one-dimensional and not particularly appealing. This is meant as a gathering of petty, annoying people, and to that end, Emma Hamilton and Daniel Weyman (as unhappily married Sally and Alec Legge), Ella Geraghty as the guest murder victim in Ariadne's game, and Elliot Barnes-Worrell as Hattie's oily cousin acquit themselves well.

Suchet has wisely done many other film and TV roles over the past 25 years, confirming what a great and versatile actor he is. Many actors might feel confined by being best known for a single role, but clearly, not Suchet. He seems to have loved every minute he's inhabited the role of Hercule Poirot, and so have we.